1. Field of the Invention
The present invention concerns a re-winding device of a watch, particularly for re-winding an automatic watch.
2. Description of Related Art
Such watches work on the principle of movement of the wrist of the user to transmit the necessary energy to the barrel. This movement allows an oscillating mass to drive a set of rotors that, by means of the demultiplication, can supply the energy in order to re-wind the spring of the barrel.
There are mainly two types of oscillating masses for automatic watches, either the complete rotation mass or the limited rotation mass. There are also the masses whose pivoting point is decentred with reference to the axis of the watch.
These differences imply that the movement of an artificial system tending to imitate the movement of the wrist must be compatible with all the automatic watches sold in the shop.
The automatic winding mechanisms are intended to keep an automatic watch operational even when its owner is not wearing it. This is particularly important for watches that have a perpetual calendar, whose stopping would mean taking it to the watchmaker in order to replace the numerous resorts in the day cycle.
This is why these watches, which are bought mainly by passionate collectors, usually are supplied directly in a box that ensures the periodic re-winding of the watch.
These boxes are manufactured in a luxurious way so as to give value to the object they contain. Such an automatic re-winding box, of the type with an electric motor, comprises a detachable base on which is placed the wristwatch, and a driving device ensured by a motor. This motor is powered by one or several batteries that generally ensure a working life of several months for the unit.
Such a device is described in the document U.S. Pat. No. 4,057,958, device that has a motor that ensures the rotation of a watch assembled on a detachable base.
A first inconvenience of this type of setting is its dimensions that rapidly discourage potential buyers. Another inconvenience is the little attractiveness of a watch assembled on such a device. In fact, it is not easy to see the object when it is placed on the base. This point is particularly important in a shop that offers a great number of these watches.
Another inconvenience is its continuous functioning, although it is at a low speed. This implies a permanent current consumption and the need to stop the motor to take the watch from its base.
Improvements of this device have been proposed that work in intermittent mode, that is, that the device has rotation phases and stop phases.
As a consequence of this the user is accustomed to seeing the re-winding device stopped without this being abnormal. For this reason it often happens that the users forget to start the re-winding device or inversely to stop it when it is not in use. The consequences can be serious if the re-winding device does not fulfil its mission.